Ls1 short block 83k miles, AFR 205cc milled 60cc for 11.5/1 compression with .040" head gaskets, biggest cam I can run without fly cutting....about a 227/236, 615"lift 113. Dual plane or single plane not sure yet, long tube headers and full 2.5" exhaust. 6010 MSD box. In Idaho 91octane is the highest at the pump so I'd have to run conservative on the timing to keep things safe. If I was to run e85 I'm hoping I could add more timing and gain better performance. What would be needed to run e85 other then a bigger carburetor? New fuel lines(no rubber). what fuel pump?

If you do decide to go E85,I would get this E85 tester from Quick Fuel Technology. Like John C mention,E85 can vary high and low octane.By getting this tester from Quick Fuel,you would know the octane level.I was told some (Pro & Con) about E85. The (Pro) about E85, Is that your performance on ride will be off the chart (Great Performance). The (Con) about E85,If the weather is cold below a certain temp in the winter. The E85 will turn into gel and also be hard to start the car. If you let your ride sit for like a months or 2,it would also turn into gel and be hard to start again.

E85 would be a waste of money and give erratic performance due to the various levels of ethanol. At only 11/1, you would be far better off just using pump 93. If you eventually use some FI, we have a different discussion.

Thank you yes that's how I got the 11.5/1 also. Just wanted to make sure I wasn't wrong on compression.
I contacted cam motion and they are the ones that speced me a 227-236 .615 113+2 and said that about the best I could do without PTV problems. I'd love to get it down to a 110 even if I need to go lower on duration but not sure yet. I'll try contacting other cam companies and pick there brain!

I have talked to two different guys local that run e85 on boosted Evo imports and they say even at 60% alky on the e85 that the octane will be greater the 91. So my thought is I should get better performance with more timing no matter what vs pump 91. The question is how much and is it worth the cost in the carburetor. I guess if I didn't like e85 really all I need to do is change the carb and go to 91 then retune timing tables with the MSD 6010 correct??

I have talked to two different guys local that run e85 on boosted Evo imports and they say even at 60% alky on the e85 that the octane will be greater the 91. So my thought is I should get better performance with more timing no matter what vs pump 91. The question is how much and is it worth the cost in the carburetor. I guess if I didn't like e85 really all I need to do is change the carb and go to 91 then retune timing tables with the MSD 6010 correct??

The (Con) about E85,If the weather is cold below a certain temp in the winter. The E85 will turn into gel and also be hard to start the car. If you let your ride sit for like a months or 2,it would also turn into gel and be hard to start again.

It will not be that hard to start if he runs e70 and where in the hell did you come up with it turning to gel and be hard to start again in cold weather?
You do realize alcohol doesn't freeze right? And that windshield washer fluid has high alcohol content so it doesn't freeze...so why would his fuel turn to goo??? I run E70-E85 in my fuel cell all year and drive it when the roads are clean ( No snow or salt) It fires up even below zero, I just have to let it run a few minutes to get some temperature in the engine before I drive away. I fill the fuel cell in the fall and don't drive it enough to use the 19 gallons the cell holds so the same fuel sits for months and guess what....it runs like a champ!

Quote:

Originally Posted by gametech

E85 would be a waste of money and give erratic performance due to the various levels of ethanol. At only 11/1, you would be far better off just using pump 93. If you eventually use some FI, we have a different discussion.

As stated above E60 and up has roughly the same anti-knock ability as E85 so it should really be that noticeable other than running slightly rich with the lower Ethanol content. If you think about it for a minute....when the air is cool the engine will want more fuel anyway so running slightly rich is not a bad thing when using a carb in the winter, Unlike injection that will adjust the tune itself as the air gets colder a carb has to be jetted up to compensate for the better air...so less ethanol and more gasoline is still going in the right direction in the winter as long as you don't run below E60 or so.
A person also has the option of buying E98 and adding it to E70 to bring the Ethanol content up. Ethanol has been proven to make more torque and power and run cleaner in an engine that has a compression ratio high enough to make use of the extra octane.

Most stations in the Midwest go from summer blend (E85) To winter blend (E70) So tune to E85 in warm weather and the worst that can happen is the car runs a little rich if you can't find e85 right away. You can always back the timing off a little if you are worried about detonation until you get better fuel in the tank. The only downside I've found with Ethanol is finding it on longer road trips.

It will not be that hard to start if he runs e70 and where in the hell did you come up with it turning to gel and be hard to start again in cold weather?
You do realize alcohol doesn't freeze right? And that windshield washer fluid has high alcohol content so it doesn't freeze...so why would his fuel turn to goo??? I run E70-E85 in my fuel cell all year and drive it when the roads are clean ( No snow or salt) It fires up even below zero, I just have to let it run a few minutes to get some temperature in the engine before I drive away. I fill the fuel cell in the fall and don't drive it enough to use the 19 gallons the cell holds so the same fuel sits for months and guess what....it runs like a champ!

As stated above E60 and up has roughly the same anti-knock ability as E85 so it should really be that noticeable other than running slightly rich with the lower Ethanol content. If you think about it for a minute....when the air is cool the engine will want more fuel anyway so running slightly rich is not a bad thing when using a carb in the winter, Unlike injection that will adjust the tune itself as the air gets colder a carb has to be jetted up to compensate for the better air...so less ethanol and more gasoline is still going in the right direction in the winter as long as you don't run below E60 or so.
A person also has the option of buying E98 and adding it to E70 to bring the Ethanol content up. Ethanol has been proven to make more torque and power and run cleaner in an engine that has a compression ratio high enough to make use of the extra octane.

Most stations in the Midwest go from summer blend (E85) To winter blend (E70) So tune to E85 in warm weather and the worst that can happen is the car runs a little rich if you can't find e85 right away. You can always back the timing off a little if you are worried about detonation until you get better fuel in the tank. The only downside I've found with Ethanol is finding it on longer road trips.

And exactly what part of my post did you feel was misinformation? Changing AFR by a significant amount will change performance, so it would be erratic. E85 is more expensive to run than pump gasoline due to far worse MPG. I know that he could gain power strictly due to the high oxygen content of ethanol fuels, but would that really make a big difference for an autocross car? Isn't the repeatability of consistently making the same power on each tank of gas a benefit? As for timing, an 11.5/1 motor on 93 probably won't be timing limited. Since he later said 91 octane, that may be a different story.

What is with all these low compression builds wanting to run e85? Do you just like throwing money out the window? Youíre gonna get horrible gas mileage, no real power gains - except now you get to pay even more for gas and you have to drive way out of your way to get it.

This isnít a mustang, a 2-valve head doesnít flow anywhere near enough, youíre not gonna see **** for gains with 11.5:1. If you canít build your engine with some real CR like 13-15:1, donít even bother. You people watch way too many YouTube videos. Pick up a Hot Rod magazine or something.